Ecotec head bolt torque?

[Selby Troy]

Gday fine Commodore people. Installing heads tomorrow on the ecotec VT and getting differing opinions on torque specs. The manual I downloaded says, in sequence:

Stage 1. 34Nm.

Stage 2. 90 degrees not exceeding 90Nm.

Stage 3. A further 90 degrees.

Problem is everywhere else I've read says stage 3 is 90Nm not an extra 90 degrees. What's the go?

 

[ant797]

Go with the manual Ecotec is in a variety of comodores it might differ model to model if you have a manual for a VT stick with that

 

[Selby Troy]

Cheers mate, thanks for the reply. Gonna go with stopping at 90 Nm on the third pass as that's what everywhere else says, including the card the gaskets came with. Maybe the online manual I have got the wording all ar@e about.

 

[shane_3800]

The bolts probably start yeilding at 90nm If you have an electronic torque wrench you can see the torque reading while doing the degrees. I bet at 90deg you'll be around 90nm most 4cyl ulp engine are around 90-110nm when brining the bolts into yeild.

 

[Gw33dz]

I just read the same in my manual, further 90 degrees. I assumed that you should hit 90nm before getting the full second 90 degree turn. I haven't done it yet, it's just that the manual says if you hit 90nm on the first 90 degree turn to stop there, so i imagine that you won't complete the second 90 degree turn without hitting 90nm. Let us know how you go.

 

[mechanic]

In case you weren't aware, use new bolts for any torque setting requiring an angle (called torque to yield).
They stretch during tightening and are not reusable.

 

[shane_3800]

In case you weren't aware, use new bolts for any torque setting requiring an angle (called torque to yield).
They stretch during tightening and are not reusable.

That is incorrect. Torque to yeild bolts can be reused in quite a few aplications. If they're one use bolts the information will state this and advise the bolts to be renewed. When a torque to yeild bolt can be reused most of the time you're provided with a bolt maximum length spec. LS1 bolts contrary to popular belife can actually be reused if you know what you're doing. On a customers car I would not reuse LS head bolts but if it was mine I would.
I will post a video explaining torque to yeild bolts.

 

[shane_3800]

 

[shane_3800]

This video outlines the facts around reusing LS1 head bolts just for those interested it's not really on subject.

 

[losh1971]

Pretty sure you need to replace head bolts on any Holden V6. Same with most engines these days.